X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=67680b1fbac52c46360109abdabbd6bcf585863a;hp=81208ac2262b87b3a7113d1297ade6218e12c268;hb=c02613860a3836bb85da25ae2fed9f1351ba27a5;hpb=a96cba0ec89e5a3bbd435fccca652678c9fd20a7 diff --git a/src/position.cpp b/src/position.cpp index 81208ac2..67680b1f 100644 --- a/src/position.cpp +++ b/src/position.cpp @@ -207,7 +207,6 @@ void Position::from_fen(const std::string& fen) { castleRightsMask[make_square(initialQRFile, RANK_8)] ^= BLACK_OOO; find_checkers(); - find_hidden_checks(); st->key = compute_key(); st->pawnKey = compute_pawn_key(); @@ -321,6 +320,29 @@ void Position::copy(const Position &pos) { } +/// Position:pinned_pieces() returns a bitboard of all pinned (against the +/// king) pieces for the given color. +Bitboard Position::pinned_pieces(Color c) const { + + Bitboard p; + Square ksq = king_square(c); + return hidden_checks(c, ksq, p) | hidden_checks(c, ksq, p); +} + + +/// Position:discovered_check_candidates() returns a bitboard containing all +/// pieces for the given side which are candidates for giving a discovered +/// check. The code is almost the same as the function for finding pinned +/// pieces. + +Bitboard Position::discovered_check_candidates(Color c) const { + + Bitboard p; + Square ksq = king_square(opposite_color(c)); + return hidden_checks(c, ksq, p) | hidden_checks(c, ksq, p); +} + + /// Position:hidden_checks<>() returns a bitboard of all pinned (against the /// king) pieces for the given color and for the given pinner type. Or, when /// template parameter FindPinned is false, the pinned pieces of opposite color @@ -446,34 +468,19 @@ void Position::find_checkers() { st->checkersBB = attacks_to(king_square(us), opposite_color(us)); } -/// Position:find_hidden_checks() computes the pinned, pinners and dcCandidates -/// bitboards. There are two versions of this function. One takes a color and -/// computes bitboards relative to that color only, the other computes both -/// colors. Bitboard checkersBB must be already updated. - -void Position::find_hidden_checks(Color us) { - Bitboard p1, p2; - Color them = opposite_color(us); - Square ksq = king_square(them); - st->pinned[them] = hidden_checks(them, ksq, p1) | hidden_checks(them, ksq, p2); - st->pinners[them] = p1 | p2; - st->dcCandidates[us] = hidden_checks(us, ksq, p1) | hidden_checks(us, ksq, p2); -} +/// Position::pl_move_is_legal() tests whether a pseudo-legal move is legal -void Position::find_hidden_checks() { +bool Position::pl_move_is_legal(Move m) const { - for (Color c = WHITE; c <= BLACK; c++) - find_hidden_checks(c); + return pl_move_is_legal(m, pinned_pieces(side_to_move())); } - -/// Position::pl_move_is_legal() tests whether a pseudo-legal move is legal - -bool Position::pl_move_is_legal(Move m) const { +bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { assert(is_ok()); assert(move_is_ok(m)); + assert(pinned == pinned_pieces(side_to_move())); // If we're in check, all pseudo-legal moves are legal, because our // check evasion generator only generates true legal moves. @@ -521,7 +528,7 @@ bool Position::pl_move_is_legal(Move m) const { // A non-king move is legal if and only if it is not pinned or it // is moving along the ray towards or away from the king. - return ( !bit_is_set(pinned_pieces(us), from) + return ( !bit_is_set(pinned, from) || (direction_between_squares(from, ksq) == direction_between_squares(move_to(m), ksq))); } @@ -530,15 +537,21 @@ bool Position::pl_move_is_legal(Move m) const { bool Position::move_is_check(Move m) const { + Bitboard dc = discovered_check_candidates(side_to_move()); + return move_is_check(m, dc); +} + +bool Position::move_is_check(Move m, Bitboard dcCandidates) const { + assert(is_ok()); assert(move_is_ok(m)); + assert(dcCandidates == discovered_check_candidates(side_to_move())); Color us = side_to_move(); Color them = opposite_color(us); Square from = move_from(m); Square to = move_to(m); Square ksq = king_square(them); - Bitboard dcCandidates = discovered_check_candidates(us); assert(color_of_piece_on(from) == us); assert(piece_on(ksq) == piece_of_color_and_type(them, KING)); @@ -680,63 +693,20 @@ inline void Position::update_checkers(Bitboard* pCheckersBB, Square ksq, Square } -/// Position::update_hidden_checks() udpates pinned, pinners and dcCandidates -/// bitboards incrementally, given the move. It is called in do_move and is -/// faster then find_hidden_checks(). - -void Position::update_hidden_checks(Square from, Square to) { - - Color us = sideToMove; - Color them = opposite_color(us); - Square ksq = king_square(opposite_color(us)); - - Bitboard moveSquares = EmptyBoardBB; - set_bit(&moveSquares, from); - set_bit(&moveSquares, to); - - // Our moving piece could have been a possible pinner or hidden checker behind a dcCandidates? - bool checkerMoved = (st->dcCandidates[us] | st->pinners[them]) && (moveSquares & sliders()); - - // If we are moving from/to an opponent king attack direction and we was a possible hidden checker - // or there exsist some possible hidden checker on that line then recalculate the position - // otherwise skip because our dcCandidates and opponent pinned pieces are not changed. - if ( (moveSquares & RookPseudoAttacks[ksq]) && (checkerMoved || (rooks_and_queens(us) & RookPseudoAttacks[ksq])) - || (moveSquares & BishopPseudoAttacks[ksq]) && (checkerMoved || (bishops_and_queens(us) & BishopPseudoAttacks[ksq]))) - find_hidden_checks(us); - - ksq = king_square(us); - - if (ksq == to) - { - find_hidden_checks(them); - return; - } - - // It is possible that we have captured an opponent hidden checker? - Bitboard checkerCaptured = st->capture && (st->dcCandidates[them] || bit_is_set(st->pinners[us], to)); - - // If we are moving from/to an our king attack direction and there was/is some possible - // opponent hidden checker then calculate the position otherwise skip because opponent - // dcCandidates and our pinned pieces are not changed. - if ( (moveSquares & RookPseudoAttacks[ksq]) && (checkerCaptured || (rooks_and_queens(them) & RookPseudoAttacks[ksq])) - || (moveSquares & BishopPseudoAttacks[ksq]) && (checkerCaptured || (bishops_and_queens(them) & BishopPseudoAttacks[ksq]))) - find_hidden_checks(them); -} - - /// Position::do_move() makes a move, and saves all information necessary /// to a StateInfo object. The move is assumed to be legal. /// Pseudo-legal moves should be filtered out before this function is called. void Position::do_move(Move m, StateInfo& newSt) { + do_move(m, newSt, discovered_check_candidates(side_to_move())); +} + +void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { + assert(is_ok()); assert(move_is_ok(m)); - // Get now the current (before to move) dc candidates that we will use - // in update_checkers(). - Bitboard oldDcCandidates = discovered_check_candidates(side_to_move()); - // Copy some fields of old state to our new StateInfo object (except the // captured piece, which is taken care of later) and switch state pointer // to point to the new, ready to be updated, state. @@ -842,16 +812,14 @@ void Position::do_move(Move m, StateInfo& newSt) { Square ksq = king_square(them); switch (piece) { - case PAWN: update_checkers(&st->checkersBB, ksq, from, to, oldDcCandidates); break; - case KNIGHT: update_checkers(&st->checkersBB, ksq, from, to, oldDcCandidates); break; - case BISHOP: update_checkers(&st->checkersBB, ksq, from, to, oldDcCandidates); break; - case ROOK: update_checkers(&st->checkersBB, ksq, from, to, oldDcCandidates); break; - case QUEEN: update_checkers(&st->checkersBB, ksq, from, to, oldDcCandidates); break; - case KING: update_checkers(&st->checkersBB, ksq, from, to, oldDcCandidates); break; + case PAWN: update_checkers(&(st->checkersBB), ksq, from, to, dcCandidates); break; + case KNIGHT: update_checkers(&(st->checkersBB), ksq, from, to, dcCandidates); break; + case BISHOP: update_checkers(&(st->checkersBB), ksq, from, to, dcCandidates); break; + case ROOK: update_checkers(&(st->checkersBB), ksq, from, to, dcCandidates); break; + case QUEEN: update_checkers(&(st->checkersBB), ksq, from, to, dcCandidates); break; + case KING: update_checkers(&(st->checkersBB), ksq, from, to, dcCandidates); break; default: assert(false); break; } - - update_hidden_checks(from, to); } // Finish @@ -1003,9 +971,6 @@ void Position::do_castle_move(Move m) { // Update checkers BB st->checkersBB = attacks_to(king_square(them), us); - - // Update hidden checks - find_hidden_checks(); } @@ -1096,9 +1061,6 @@ void Position::do_promotion_move(Move m) { // Update checkers BB st->checkersBB = attacks_to(king_square(them), us); - - // Update hidden checks - find_hidden_checks(); } @@ -1181,9 +1143,6 @@ void Position::do_ep_move(Move m) { // Update checkers BB st->checkersBB = attacks_to(king_square(them), us); - - // Update hidden checks - find_hidden_checks(); } @@ -1568,11 +1527,6 @@ int Position::see(Square from, Square to) const { Color us = (from != SQ_NONE ? color_of_piece_on(from) : opposite_color(color_of_piece_on(to))); Color them = opposite_color(us); - // Initialize pinned and pinners bitboards - Bitboard pinned[2], pinners[2]; - pinned[us] = pinned_pieces(us, pinners[us]); - pinned[them] = pinned_pieces(them, pinners[them]); - // Initialize pieces Piece piece = piece_on(from); Piece capture = piece_on(to); @@ -1605,17 +1559,6 @@ int Position::see(Square from, Square to) const { | (pawn_attacks(WHITE, to) & pawns(BLACK)) | (pawn_attacks(BLACK, to) & pawns(WHITE)); - // Remove our pinned pieces from attacks if the captured piece is not - // a pinner, otherwise we could remove a valid "capture the pinner" attack. - if (pinned[us] != EmptyBoardBB && !bit_is_set(pinners[us], to)) - attackers &= ~pinned[us]; - - // Remove opponent pinned pieces from attacks if the moving piece is not - // a pinner, otherwise we could remove a piece that is no more pinned - // due to our pinner piece is moving away. - if (pinned[them] != EmptyBoardBB && !bit_is_set(pinners[them], from)) - attackers &= ~pinned[them]; - if (from != SQ_NONE) break; @@ -1678,12 +1621,6 @@ int Position::see(Square from, Square to) const { lastCapturingPieceValue = seeValues[pt]; c = opposite_color(c); - // Remove pinned pieces from attackers - if ( pinned[c] != EmptyBoardBB - && !bit_is_set(pinners[c], to) - && !(pinners[c] & attackers)) - attackers &= ~pinned[c]; - // Stop after a king capture if (pt == KING && (attackers & pieces_of_color(c))) {